Protective garment containing a stiff composite

ABSTRACT

A protective garment containing a composite which has an alternating pattern containing groupings of woven fabric and groupings of biaxially oriented thermoplastic films. The composite has a thickness of greater than about 5 mm. Each grouping of woven fabric contains at least one woven fabric layer, each woven fabric layer containing tape elements having a base layer of a strain oriented olefin polymer disposed between covering layers of a heat fusible olefin polymer. Each grouping of biaxially oriented thermoplastic films contain at least one biaxially oriented thermoplastic film which has a core layer of thermoplastic disposed between covering layers of a thermoplastic able to bond to polypropylene.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application62/519,974 “Protective Garment Containing a Stiff Composite”, filed onJun. 15, 2017.

TECHNICAL FIELD

The present invention relates to protective garments with componentsmade from stiff composites. More particularly, the invention related toprotective garments with components made from composites containing analternating pattern containing groupings of woven fabric and groupingsof biaxially oriented thermoplastic films.

BACKGROUND

Composites are being utilized more in different applications where thereis a need for a specific stiffness and/or toughness while minimizingweight and cost. There is a need for protective garments to usecomposites for the desired physical properties at a low price point.

BRIEF SUMMARY

The disclosure relates to a protective garment containing a compositehaving an upper and lower surface and an alternating pattern containinggroupings of woven fabric and groupings of biaxially orientedthermoplastic films. The composite has a thickness defined to be thedistance between the upper and lower surfaces of greater than about 5mm. Each grouping of woven fabric comprises at least one woven fabriclayer, each woven fabric layer comprising warp tape elements in a warpdirection and weft tape elements in a weft direction which isapproximately perpendicular to the warp direction. The tape elementscomprise a base layer of a strain oriented olefin polymer disposedbetween covering layers of a heat fusible olefin polymer. The warp tapeelements and weft tape elements within the woven fabric layer areinterwoven and crossover each other at crossover points and the warpelements are bonded to the weft elements within the woven fabric layerat the crossover points. Each grouping of biaxially orientedthermoplastic films comprises at least one biaxially orientedthermoplastic film, where each film comprises a core layer ofthermoplastic disposed between covering layers of a thermoplastic ableto bond to polypropylene. The layers within each grouping are bondedtogether, the woven fabric layers and adjacent biaxially orientedthermoplastic films are bonded together, and the total thickness ofwoven fabric layers to biaxially oriented thermoplastic films within thecomposite is between about 2:1 to 1:50.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates schematically a cross-section of one embodiment ofthe composite.

DETAILED DESCRIPTION

Referring now to FIG. 1, there is shown one embodiment of the composite10. The composite has an upper surface 10 a and a lower surface 10 b.The composite also has an alternating pattern containing groupings ofwoven fabric 100 and groupings of biaxially oriented thermoplastic films200. In the embodiment shown in FIG. 1, there are 3 groupings of thewoven fabric 100 and 2 groupings of biaxially oriented thermoplasticfilms 200, where the upper 10 a and lower 10 b surfaces of the compositeare formed by the woven fabric groupings 100. In one embodiment, thecomposite contains at least one grouping of woven fabric 100 and inanother embodiment, the composite contains at least 2 groupings of wovenfabric 100. In another embodiment, the composite comprises at least 3,at least 4, or at least 5 groupings of woven fabric 100. In oneembodiment, the composite contains at least one grouping of biaxiallyoriented thermoplastic films 200 and in another embodiment, thecomposite contains at least 2 groupings of biaxially orientedthermoplastic films 200. In another embodiment, the composite comprisesat least 3, at least 4, or at least 5 groupings of biaxially orientedthermoplastic films 200. Preferably, the groupings form an alternatingpattern (for example, grouping 100, grouping 200, grouping 100, grouping200), but the composite may also contain repeating groupings, randompatterns of different groupings, or additional films, layers, fabrics,or additional materials between the groupings, between the layers, or onthe outside of the composite 10. The number of groupings is selected forthe end use properties such as stiffness, toughness, and thickness.

Each grouping of woven fabric 100 comprises at least one woven fabriclayer 110, each woven fabric layer comprising warp tape elements in awarp direction and weft tape elements in a weft direction which isapproximately perpendicular to the warp direction. In the embodiment ofFIG. 1, the groupings of woven fabric 100 each contain 3 woven fabriclayers. The groupings may contain as few as one woven fabric layer or asmany as required for the desired end use article. In one embodiment, thegroupings of the woven fabric 100 contain at least 2 woven fabriclayers, more preferably at least 3 woven fabric layers. In anotherembodiment, the groupings of the woven fabric 100 contain at least 4, atleast 5, or at least 6 woven fabric layers. In another preferredembodiment, the groupings of the woven fabric 100 contain between 1 and3 woven fabric layers. The groupings of woven fabric layers 100 withinthe composite may all contain the same number of fabric layers (such asshown in FIG. 1), or the different groupings of woven fabric 100 maycontain different numbers of woven fabric layers within the composite10. The same number of layers with in the groupings may be used tosimplify manufacture of the composite. Different numbers of layers inthe groupings may be used to tailor strength and stiffnesscharacteristics through the composite 10 or may use additional or fewerlayers in the groupings forming the outer surfaces 10 a and 10 b of thecomposite 10. In one embodiment, the composite 10 preferably includes atleast 10 groupings 100 and 10 groupings 200. In another embodiment, thecomposite 10 preferably includes at least 20 groupings 100 and 20groupings 200. In another embodiment, the composite 10 preferablyincludes at least 25 groupings 100 and 25 groupings 200.

Preferably, each woven fabric layer has a thickness of between about0.05 mm and 0.35 mm, more preferably between about 0.10 mm and 0.20 mm.Preferably, the groupings of woven fabric have a thickness of betweenabout 0.05 mm and 1.0 mm, more preferably between about 0.10 mm and 0.45mm.

The tape elements comprise a base layer of a strain oriented olefinpolymer disposed between covering layers of a heat fusible olefinpolymer. The warp tape elements 115 and weft tape elements 113 withinthe woven fabric layer are interwoven and crossover each other atcrossover points and the warp elements 115 are bonded to the weftelements 113 within the woven fabric layer 110 at the crossover points.

Each grouping of biaxially oriented thermoplastic films 200 comprises atleast one biaxially oriented thermoplastic film 210, where each filmcomprises a core layer of thermoplastic disposed between covering layersof a thermoplastic able to bond to polypropylene. In the embodiment ofFIG. 1, the groupings of biaxially oriented thermoplastic films 200 eachcontain 5 biaxially oriented thermoplastic films 210. The groupings maycontain as few as one biaxially oriented thermoplastic film or as manyas required for the desired end use article. In one embodiment, thegroupings of the biaxially oriented thermoplastic films 200 contain atleast 2 biaxially oriented thermoplastic films 210, more preferably atleast 3 biaxially oriented thermoplastic films. In another embodiment,the groupings of biaxially oriented thermoplastic films 200 contain atleast 4, at least 5, or at least 6 biaxially oriented thermoplasticfilms. The groupings of biaxially oriented thermoplastic films 200within the composite may all contain the same number of biaxiallyoriented thermoplastic films (such as shown in FIG. 1), or the differentgroupings of biaxially oriented thermoplastic films 100 may containdifferent numbers of biaxially oriented thermoplastic films within thecomposite 10. The same number of layers within the groupings may be usedto simplify manufacture of the composite. The biaxially orientedthermoplastic films 210 within each grouping are bonded together. Thebiaxially oriented thermoplastic films do more than simply add bulk tothe composite or act as an adhesive between the groupings of fabriclayers 100, the biaxially oriented thermoplastic films contribute to thephysical characteristics of the composite 10.

Preferably, each biaxially oriented thermoplastic film has a thicknessof between about 0.01 and 0.25 mm, more preferably between about 0.01and 0.08 mm. Preferably, the groupings of biaxially orientedthermoplastic films have a thickness of between about 0.05 and 5.0 mm,more preferably between about 0.10 and 1.0 mm.

The composite 10 contains at least 1 grouping of woven fabric 100 and atleast 1 grouping of biaxially oriented thermoplastic films 200. In oneembodiment, the composite contains 2 groupings of woven fabric 100 and 1grouping of biaxially oriented thermoplastic films 200, where thegroupings 100 sandwich the grouping 200. In another embodiment, thegroupings are selected such that both the upper and lower surfaces 10 a,10 b are formed by the woven fabric groupings 100. In anotherembodiment, the groupings biaxially oriented thermoplastic films 200form the upper and lower surfaces 10 a, 10 b. In another embodiment, agrouping 100 forms one of the upper or lower surfaces 10 a, 10 b, agrouping 200 forms the opposite surface.

The composite 10 preferably has a thickness defined to be the distancebetween the upper 10 a and lower 10 b surfaces of greater than about 5mm. In another embodiment, the composite 10 preferably has a thicknessof greater than about 7 mm, more preferably greater than about 10 mm.The composite 10 preferably has a stiffness of greater than about 150N-m, more preferably greater than 500 N-m. This higher stiffness allowsfor end use applications where flexing of the composite may not bedesirable.

The term “bonded” means held together, adhered, or attached and may alsobe referred to as fused. Preferably, the parts of the composite 10 arebonded together using the covering layers of a heat fusible olefinpolymer in the tape elements within the fabric layers 110 and thecovering layers of a thermoplastic able to bond to polypropylene of thebiaxially oriented thermoplastic films 210. This bonding or fusing maybe accomplished by using heat to partially melt and bond the elementstogether or by using an additional adhesive that may be heat, light, ormonomer initiator, or UV activated.

The composite 10 is fully bonded together, within each woven fabriclayer 110, the warp elements 115 are bonded to the weft elements 113 atthe crossover points, the tape elements from one woven fabric layer arebonded to tape elements from adjacent woven fabric layers within thegroupings of woven fabric, the biaxially oriented thermoplastic films100 are bonded to adjacent biaxially oriented thermoplastic films 100within the groupings of biaxially oriented thermoplastic films 200, andtape elements adjacent biaxially oriented thermoplastic films (fromadjacent groupings 100, 200) are bonded together. This forms a strongand high performing composite material. Having the elements within thecomposite 10 being fused to one another provides resistance tounraveling and may provide better tear resistance, higher tensilemodulus, and better stability.

There may be embodiments where the bonds are not as strong, i.e., notall of the tape elements and/or biaxially oriented thermoplastic filmsare bonded as much as they could be. This may be advantageous forflexibility and/or other performance characteristics such as ballisticsperformance.

The layers, the woven fabric layers and adjacent biaxially orientedthermoplastic films are bonded together forming the composite. Withinthe composite, the total thickness of woven fabric layers (of all of thegroupings of woven fabric) to biaxially oriented thermoplastic films (ofall of the groupings of biaxially oriented thermoplastic films) isbetween about 3:1 to 1:50. More preferably the ratio is between about2:1 to 1:20, more preferably between about 1:1 to 1:10.

The first woven layer 100 and the second woven layer 200 contain fibersin the warp and weft direction, where the fibers may be any suitablefiber. Preferably, the fibers are tape elements. Preferably, the tapeelements are monofilament fibers having a rectangular cross-section andare continuous. The tape element is considered to have a rectangularcross-section even if one or more of the corners of the rectangular areslightly rounded or if the opposing sides are not perfectly parallel.Having a rectangular cross-section may be preferred for a variety ofreasons. Firstly, the surface available for bonding is greater.Secondly, during a de-bonding event the whole width of the tape is undertension and shear points are significantly reduced or eliminated.

In one embodiment, the tape elements have a cross-sectional shape with awidth between about 0.05 mm and 10 mm more preferably between about 0.1mm and 5 mm and a height between about 10 μm and 500 μm more preferablybetween about 20 μm and 200 μm. In one embodiment, the aspect ratiocomparing the width of the rectangular cross-section to the height ofthe rectangular cross-section is between about 0.25 and 500.

The tape elements may be formed from any suitable material. Preferably,the tape elements comprise a thermoplastic polymer. Some suitablematerials include, but are not limited to, polypropylenes,polyethylenes, polyesters, polyamides, polyethers, copolymers of any ofthe above; glass, aramid, carbon, ceramic, nylon, polyetherimide,polyamide-imide, polyphenylene sulfide, polysulfones, polyimide,conjugated polymers, mineral fiber, natural fibers, metallic fiber ormixtures thereof. In one embodiment, the tape elements 50 have a tensilemodulus of greater than 10 grams per denier as measured by ASTM method3811-07 and/or a tensile strength of at least 100 MPa. In oneembodiment, the tape elements comprise polypropylene. Polypropylene maybe preferred for some applications due to its strength, ability to beoriented, and low cost.

In one embodiment, the tape elements contain a base layer of a strainoriented olefin polymer disposed between covering layers of a heatfusible olefin polymer. Alternatively, it is contemplated that only asingle covering layer may be present. The base layer of the tapeelements is preferably compatibly bonded to each of covering layersbetween their contiguous surfaces. It is further contemplated that thecovering layers have a softening temperature, or melting temperature,lower than that of the base layer. The base layer may be, but is notlimited to, a polyolefin polymer such as polypropylene, polyethylene, apolyester such as polyethyleneterephthalate, or a polyamide such asNylon 6 or Nylon 6-6. According to one potentially preferred practice,the base layer may be polypropylene or polyethylene. The base layer mayaccount for about 50-99 wt. % of the tape element, while the coveringlayers account for about 1-50 wt. % of the tape element. Preferably, thebase and covering layers are made up of the same class of materials toprovide an advantage with regard to recycling and adhesion.

In an embodiment where the base layer contains polypropylene, thematerial of covering layers is preferably a copolymer of propylene andethylene or an α-olefin and has a lower melting temperature than thebase layer. One example of a suitable tape element is TEGRIS™ availablefrom Milliken & Company.

The tape elements may be produced in any suitable manner. In oneembodiment, the tape elements may be formed by slitting a film. The filmmay be formed by any conventional means of extruding such multilayerpolymeric films. By way of example, and not limitation, the film may beformed by blown film or cast film extrusion. The film is then cut into amultiplicity of longitudinal strips of a desired width by slitting thefilm to yield tape elements having the desired cross-sections. The tapeelements may then be drawn in order to increase the orientation of thetape element so as to provide increased strength and stiffness of thematerial. In another embodiment, an already oriented (mono or biaxially) film is then slit into tape elements.

In another embodiment, the tape elements are extruded from a slit diethen oriented. The process begins with slit extruding molten polymer toform fibers having a rectangular cross-section. The die typicallycontains between 5 and 60 slits, each one forming a fiber. In oneembodiment, the each slit die has a width of between about 15 mm and 50mm and a thickness of between about 0.6 and 2.5 mm. The fibers onceextruded are typically 4 to 12 mm wide and after drawing are typically 1to 3 mm wide. The fibers may be extruded having one layer or may have asecond layer and/or a third layer using co-extrusion.

The woven fabric layers 100 may be any suitable textile layer. Thisincludes but is not limited to a woven, nonwoven, unidirectional, orknit textile. The textile layer contains interstices which are spacesbetween the fibers of the textile layer. The tighter the textile layerconstruction, the smaller the interstices.

Preferably, the woven fabric layers 110 are woven layers where warp tapeelements running in the warp direction are interwoven with weft tapeelements running in the weft direction in transverse relation to thewarp tape elements. The weft tape elements are interwoven with the warptape elements such that a given weft extends in a predefined crossingpattern above and below the warp. Where the warp and weft elements crossover each other are defined to be cross-over points. In one embodiment,the weft tape elements and the warp tape elements are formed into a socalled plain weave wherein each weft tape element passes over a warptape element and thereafter passes under the adjacent warp tape elementin a repeating manner across the full width of the woven layer. However,it is also contemplated that any number of other weave constructions aswill be well known to those of skill in the art may likewise beutilized. By way of example only, and not limitation, it is contemplatedthat the weft tape elements may pass over two or more adjacent warp tapeelements before transferring to a position below one or more adjacentwarp fibers thereby forming a twill weave. The term “interwoven” ismeant to include any construction incorporating inter-engaging formationfibers. In one embodiment, the woven layers are, for example, plain,satin, twill, basket-weave, poplin, jacquard, and crepe weave wovenlayers. Preferably, the woven layers are either a plain or twill weavewoven layer. It has been shown that plain weaves have good abrasion andwear characteristics. A twill weave has been shown to have goodaesthetic properties and for compound curves so may also be preferredfor molded parts or rubber articles. Within the groupings of wovenfabric 100 and between the groupings of woven fabric, the woven fabriclayers 110 be the same or different. They might be different in theirtape element construction, aspect ratio, materials or in their weaveformation.

Preferably, the biaxially oriented thermoplastic films have a core layerof thermoplastic disposed between covering layers of a thermoplasticable to bond to polypropylene. Preferably, the tensile strength in themachine direction of the film is between 100 and 275 MPa and in thetransverse direction of between about 140 and 300 MPa (testing accordingto ASTM D882).

One method for producing the composite 10 is to stack all of the layerstogether (all of the woven fabric layers 110 and the biaxially orientedthermoplastic films 210) and then consolidate the entire composite 10 atonce. In another embodiment, the groupings 100, 200 may be consolidatedfirst, then stacked together and reconsolidated together. Consolidationoccurs when heat and optionally pressure is added such that all of theelements bond or fuse together to form a composite that may be handledwithout falling apart. Preferably, the composite is heated at atemperature below the softening point of the core of tape elements andthe films 210 and preferably higher than the melting point of thecovering layers of the tape elements and the films 210.

Consolidation may be performed by any suitable method. Heated batch orplaten presses may be used for consolidation. In one exemplary practice,autoclaves or vacuum bags may be used to provide the pressure duringconsolidation. Continuous consolidation methods such as calendaring oruse of a single or double belt laminator or extrusion laminator maylikewise be employed. It is contemplated that any other suitable pressmay likewise be used to provide appropriate combinations of temperature,pressure, and residence time.

The composite may contain additional fibers, additives, or layers.Examples of additional fibers that may be incorporated include, but arenot limited to fibers made from highly oriented polymers, such asgel-spun ultrahigh molecular weight polyethylene fibers, melt-spunpolyethylene fibers, melt-spun nylon fibers, melt-spun polyester fibers,sintered polyethylene fibers, rigid-rod polymers, carbon fibers, aramidfibers, glass fibers, polylactic acid fibers, and natural fibers such ascotton. Additives, such as processing aids, colorants (dyes orpigments), or fillers may be added.

“Protective garment” is defined to be any article that is designed to beworn on the body. This includes, but is not limited to, shoes (includingboots, etc), pants, shirts, jackets, coats, vests, hats, helmets, kneepads, shoulder pads, body armor, athletic cups, and belts. The compositemay be formed directly into the protective garment, may be encapsulatedwithin a material, be sewn or otherwise attached to the garment, or maybe at least partially enclosed in a pouch or pocket that is part of oris attached to a garment.

The composite may be used in any suitable part of the protectivegarment. In one embodiment, the garment is a shoe and the compositeforms at least a portion of the sole. The composite has been shown toprovide good protection for body armor (for both military and sportsrelated activities).

The composite is beneficial to the garment for providing a low weight,but tough material to the garment. The composite can provide a level ofstiffness and protection to the wearer through the use of the compositein the garment and may provide protection to various threats (such asbullets, shanks, and knives). The composite may be molded or shaped forcontour, structure, or appearance reasons by cold or hot formingmethods.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

What is claimed is:
 1. A protective garment comprising a compositehaving an upper and lower surface comprising an alternating patterncontaining groupings of woven fabric and groupings of biaxially orientedthermoplastic films, wherein the composite has a thickness defined to bethe distance between the upper and lower surfaces of greater than about5 mm, wherein the composite comprises; wherein each grouping of wovenfabric comprises at least one woven fabric layer, each woven fabriclayer comprising warp tape elements in a warp direction and weft tapeelements in a weft direction which is approximately perpendicular to thewarp direction, wherein the tape elements comprise a base layer of astrain oriented olefin polymer disposed between covering layers of aheat fusible olefin polymer, wherein the warp tape elements and wefttape elements within the woven fabric layer are interwoven and crossovereach other at crossover points, wherein the warp elements are bonded tothe weft elements within the woven fabric layer at the crossover points;wherein each grouping of biaxially oriented thermoplastic filmscomprises at least one biaxially oriented thermoplastic film, whereineach film comprises a core layer of thermoplastic disposed betweencovering layers of a thermoplastic able to bond to polypropylene,wherein the layers within each grouping are bonded together; whereinwoven fabric layers and adjacent biaxially oriented thermoplastic filmsare bonded together; wherein the total thickness of woven fabric layersto biaxially oriented thermoplastic films within the composite isbetween about 2:1 to 1:50.
 2. The protective garment of claim 1, whereinthe garment is a helmet.
 3. The protective garment of claim 1, whereinthe garment is a vest.
 4. The protective garment of claim 1, wherein thegarment is sports protective wear.
 5. The protective garment of claim 1,wherein the composite has a stiffness of greater than about 150 N-m. 6.The protective garment of claim 1, wherein the composite comprises 2groupings of woven fabric.
 7. The protective garment of claim 1, whereinthe composite comprises 1 grouping of biaxially oriented thermoplasticfilms.
 8. The protective garment of claim 1, wherein the compositecomprises at least 2 groupings of woven fabric.
 9. The protectivegarment of claim 1, wherein the composite comprises at least 2 groupingof biaxially oriented thermoplastic films.
 10. The protective garment ofclaim 1, wherein each grouping of woven fabric comprises at least twowoven fabric layers.
 11. The protective garment of claim 1, wherein eachgrouping of biaxially oriented thermoplastic films comprises at leasttwo biaxially oriented thermoplastic films.